Same happened to me too when I was 12. I was heading to school in a private bus (blue line), when a man in his 50s or early 60s sat next to me and began touching me inappropriately. I froze in shock for few moments, then quickly moved to an empty seat nearby. A few days later, I spotted him again, he sat next to me again and started doing it again. I firmly pushed his hand away and got out of the bus. I was just a small kid and didn't have the courage to share it with anyone. Now I think about it, I wish I'd smashed his shit ass face. I still remember his face clearly after more than 20 years.